Electroplating-bath for copper



and more specifically pointed out in the claim.

UNITED STATES PATENT OFFICE.

TVILLIAM B. HOLLINGSHEAD, OF BRONXVILLE, NEWV YORK, ASSIGNOR TO JAMES G. BATTERSON, OF HARTFORD, CONNECTICUT.

ELECTROPLATING-BATH FOR COPPER.

SPECIFICATION forming part of Letters Patent No. 427,513, dated May 6, 1890.

Application filed September 23, 1889.

To all whom it may concern.-

Be it known that 1, WILLIAM B. HOLLINGS- HEAD, of Bronxville, in the town of East Chester, county of W'estchester, and State of New York, have invented certain new and useful Improvements in ElectroplatingBaths for Copper, of which the following is a full, clear, and exact description, whereby any one skilled in the art can make and use the same.

The object of my invention is to produce an electroplating-bath that shall have whileactive a predetermined and substantially constant degree of saturation, so that a metallic article may be covered with a plating of copper having certain desired characteristics as to size and arrangement of crystals, that can with certainty be duplicated or repeated at Will in subsequent platings of like articles. To this end and as a step in the manufacture of copper-plated sheets of iron, a bath is prepared with a given quantity of water as a vehicle and certain salts that when mixed with the water in proportions as hereinafter specified form What I prefer to term a conveyer, as it is the object of myinvention to produce a bath subject to but slight deterioration while active,-and serving practically as a medium through which the copper is transferred from one pole to the other of the battery.

My invention consists in an electroplatingbath composed of certain materials in proportion substantially as hereinafter described,

The composition of the electro-depositing solution or bath isas follows: At a temperature preferably less than 100 Fahrenheit dissolve thirty-two ounces of potassium tartrate in 75.5 ounces, by weight, of water. Then in a separate vessel dissolve in 75.5 ounces of water sixteen ounces of ammonium sulphate, and then mix the solutions thus prepared, and when mixed add of copper cyanide one ounce. The solution is then ready for use in the bath, and the best results are obtained by keeping it at a temperature less than 100 Fahrenheit. These proportions are based on the weight and not on the quantity of the several elements.

Serial No. 324,815. (No specimens.)

The copper cyanide used by me is preferably produced by precipitating copper from a solution of sulphate of copper with carbonate of soda, the precipitate being afterward washed in water to free it from acid and then dissolving the cyanide of potassium to point of saturation. The quantity of water to be used is variable to a limited degree in order to conform to the strength of electric current used, and also to the degree of conductivity desired in the bath or solution.

It'has been found by extended experiments that wi th this bath,when the cathode is formed of or connected to a steel or iron plate submerged in the bath, there is a perfect adhesion of the deposit of copper from the beginning of the'deposition. The first precipitation has a peculiar character from the fact of the iron being a better conductor or conveyer than the bath, this being shown by the crystals of copper, that are smaller in the first deposit than those deposited late in the process.

An examination of the work done by the use of my improved bath shows that the whole deposit is characterized by a peculiar smoothness, density, and compactness in arrangement of crystals, and for that reason theplating need not to be annealed asa preliminary to rolling, planishing, or burnishing the sheet-s in subsequent shaping or working them.

The above-described bath is used in. the ordinary manner.

I claim as my invention- A11 electroplating-bath consisting of a sol u- WILLIAM B. I-IOLLINGSHEAD.

Witnesses:

WILLIAM WILLIAMS, SAMUEL M. JANNEY, HENRY M. LOVE. 

